Improvements in computer processing power and broadband technology have led to the development of interactive systems for navigating imagery, such as geographic imagery. Some interactive map navigation systems provide a user interface with navigation controls for navigating cities, neighborhoods, and other terrain in two or three dimensions. The navigation controls enable users to tilt, pan, rotate, zoom, and activate terrain and buildings for different perspectives at an area of interest. Exemplary map imaging systems include the Google Earth and Google Maps systems by Google Inc.
The imagery used by these interactive systems can be derived by rendering geometric objects and texture objects to generate a two-dimensional or three-dimensional graphical representation of an area of interest. The geometric objects can define three-dimensional surfaces of objects and terrain depicted in the imagery. The texture objects can be mapped to the three-dimensional surfaces to add detail, surface texture, color and other features to the depicted objects and terrain.
Interactive systems for displaying imagery, such as geographic imagery, often render geometric and texture objects with low level of detail (“LOD”) (e.g. low resolution) at camera views far from an area of interest to improve performance. As the user zooms in the camera view closer to the area of interest, geometric and texture objects with higher LOD (e.g. higher resolution) are rendered to depict objects in greater detail. A user can also control a camera view to navigate between areas of interest that have geometric and texture objects rendered with the same LOD or different LOD. For example, users can “fly” or navigate around a virtual Earth, while geometric and texture objects corresponding to geographical locations are presented in varying LOD.
Ideally, systems are able to render objects fluidly at an optimum frame rate to permit smooth and uninterrupted transition between areas of interest. However, poor system performance due to hardware limitations can result in choppy transitions between areas of interest and jitter or pause as objects are being rendered in response to the desired camera view. The jitter or pause can be a visual anomaly which disrupts the user's sense of immersion in the imagery.